Jonathan D. Smith, Department of Cell Biology, NC10, Cleveland Clinic, 9500 Euclid Avenue, Cleveland OH 44195. E-mail smithj4@ccf.org ----- ----- ----- ----- HDL-cholesterol is the "good cholesterol" because of its reverse cholesterol transport and antiinflammatory activities. However, HDL and apolipoprotein A-I can lose their protective activities through changes in protein or lipid composition as well as protein modifications. Assays for dysfunctional HDL could potentially be used as a criterion for preventative therapy.